Method of manufacturing steel



Patented Oct. 10, 1922.

UNITED STATES r 1,431,621 PATENT OFFICE.

JAY O. BENEKER, OF SEATTLE, WASHINGTON, AS SIGNOR OF ONE-THIRD TOFREDERICK F. M INTOSH, F GLEN OSBORNE, PENNSYLVANIA, AND ONE-THIRDTO,WILLIAM B. SKIKLE, OF CORAOPOLIS, PENNSYLVANIA. i

METHOD OF MANUFACTURING STEEL.

No Drawing..

To all whom it may concern:

Be it known that I, JAY C. BENEKER, a citizen of the United States, aresident of Seattle, in the county of Kingand State of \Vashington, haveinvented a new and useful Improvement in Methods of Manufacturing Steel,of which the following is a specificatlon.

In the manufacture of manganese steel,

the usual practice is to add the manganese to a molten bath of steel inthe form of a ferro-allo containing about 80% manganese and a out 6%carbon. Because the commercial grades of ferromanganese are so high incarbon,a very considerable amount of carbon is added to the bath, and itis therefore very diflicult, if not entirely impossible, to economicallyproduce a low-carbon highmanganese steel. The steels which are menufactured by the usual process and which contain more than quite smallpercentages of manganese are hard and brittle because of the combinedeffect of high carbon and manganese, and they have a very limited fieldof usefulness.

The object of the invention is to provide a method whereby low-carbonhigh-manganese steel may be economically iuanufac tured withoutsubstantial departure from the usual manner of procedure followed in themaking of steel.

Low-carbon high-manganese steel as contemplated herein is steelcontaining not more than about carbon and not less than 5 about 1.00%manganese. In the practice of the invention manganese is added to amolten bath of steel in the form of a silico-nu nganese alloy, thesilicon, or a large portion of it, being eliminated by oxidizing it. In

this way, the manganese, which has less at finity for oxygen than doessilicon, becomes available for allo ing with the steel, and, the carbonof the si ico-manganese alloy being low, steel low incarbon and with thedesired percentage of manganese is produced. The method may be carriedout in various ways, but in the preferred practice the oxidation ofsilicon is brought about chiefly by blanketing the steel with a slagcontainin metallic or other oxides which may be readily reduced by thesilicon.

The invention may be practiced in various ways. According to one mannerof procedure, a melt of steel is worked down in a basic Applicationfiled March 1, 1921. Serial No. 448,896.

furnace in the usual way of making Low carbon steel, and the slag is socontrolled that it has a low silica content, preferably less than 15%.This may be done b causing the slag to have a large content 0 linie anda normal content of manganese and iron. Near the end of the heat thesilico-man'ganese is introduced into the bath, the alloy, containmg fromabout 10 to 20% silicon and 50 to 70% man anese, 'the remainder beingiron and a sma 1 amount of carbon and other impurities. The low-carboncontent of the silico-manganese as compared to ferro-manganese alloys isdue to the presence of silicon. The amount of silico-manganese thusintroduced will depend of course upon the percentage of manganesedesired in the steel. In the reaction that takes place, the silicon ofthe silico-manganese alloy, or a large ortion thereof, becomes oxidizedby the oxides of the slag, the silicon having a greater atfinity for oxyen than does manganese. This reaction ta es place lar ely because of thelow silica content of the slag. It will, of course, be understood thatsome of the silicon becomes oxidized by the oxides in the molten steel,and that some may remain in the steel. However, actual practice oi theinvention has shown that'when the method is practiced in the mannerdescribed a large portion of the silicon enters the slag as silica. Theamount of silicon remaining in the steel may be controlled by thecomposition of the slag and the period of time, after adding thesilico-nianganese, which the heat is held in the furnace before tapping.

According to another and the preferred manner of procedure, a slag ismaintained high in manganese oxides. This may be done by usingconsiderable amounts of manganese ores either with the charge or aslater additions in oxidizing the carbon of the melt. When theSiliCO-lllflngEtIlQSB is added, a larger percentage of manganese becomesalloyed with the steel for a given amount of silicO-manganese added thanin the first described manner ol procedure. A large part of the siliconreduces the manganese oxides of the slag with the double result that themanganese is reduced from the slag and becomes alloyed with the steeland the silicon is eliminated as silica in the slag. Some of the siliconmay reduce the iron oxides of the slag wth the same general result.

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The method is applicable to the manufac ture of alloy steels low incarbon and high in manganese and which also contain other allowingmetals such as chromium, molybdenum, tungsten, vanadium, copper, nickel,et cetera. For example, these alloying elements may be added as oxidesin the charge or slag and be caused to enter the steel by the strongreducing action of the silicon, or they may be added to the molten bathin the usual form of ferro-alloys or metals.

The second of the above described manners of procedure may be modifiedby removing a first oxidizing slag so as to free the molten bath fromphosphorus and other impurities, and then making up a high-manganesehigh-line slag for the reaction with the silicon. This practice is ofspecial advantage in electric furnaces, but may also be used in themanufacture of steel in other furnaces for obtaining better control ofthe process.

As a specific example of the practice of the invention, I made a melt ofsteel using as a charge 73,000 lbs. of scra'p, 17,000 lbs. of cast iron,3,800 lbs. coke, 2,000 lbs. manganese ore of about 45% manganese, and5,500 lbs. burnt lime. After the carbon content had been worked down toabout 05%, an addition of 1,000 lbs. of silicoma-nganese was made, thealloy being a 22% silicon and 55% manganese. About ten minutes later, afurther addition of 1,000 lbs. of the same silico-manganese was made,and about fifteen minutes later the heat was tapped. Analyses of samplesof the slag taken before and after the addition of the silico-manganesesowed that the silica content of the slag was increased about 41}%. Theresultiqg steel was found to contain 1.13% manganeseand .06% carbon, anda test of the steel, after being heated to redness and quenched ratherslowly and mildly, showed it to have an elastic limit of about 80,000lbs., an elongation in two inches of 25% and a reduction in area of55.4%.

The foregoing Specific example of how the method has actually beenpracticed is given, not by way of limitation, but as an illustration ofthe process and of the character of the resulting steel.

As previously stated, manganese steel made according to the process islow in carbon. Resulting from its low-carbon highmanganese content, thesteel has unexpected physical properties. It has high strength andelasticity and is remarkably ductile in proportion to its strength, andmay be advantageously used for many )urposes where strong ductile steelsare esired. Steels made according to the process which have less thanabout 0.10% carbon and more than about 1.50% manganese have specialcommercial value.

I claim:

1. The method of manufacturing steel containing not more than about 35%carbon and not less than about 1.00% manganese. which consists inintroducing a silico-manganese alloy into a molten bath of steel in itscourse of manufacture, and eliminating silicon by oxidizing it.

2. The method of manufacturing steel containing not more than about 35%carbon and not less than about 1.00% manganese, which consists inblanke'tin a 'bath of steel with a slag low in silica, introducing a.silica-manganese alloy in such bath, and eliminating silicon by reducingthe oxides of the slag. I

3. The method of manufacturing steel containing not more than, about.35'% carbon and not less than about 1.00% manga nese, which consists inblanketing a bath of steel with a sla high in manganese oxides,introducing a si ice-man anese alloy in such bath, and eliminating si'icon by its reducipg action on the manganese oxides of the s a ntestimony whereof, I have hereunto set my hand.

JAY C/BENEKE-R. J Witnesses: H. KING,

' .C. S. HUNTOON.

C Certificate of Correct ien. It. is hereby certified that the name ofthe second-mentioned assignee in Letters Patent No. 1,431,621, grantedOctober 10, 1922, upon the ap Iication of Jay C. Beneker, of Seattle,Washington, for an improvement in Methods of Maimfacturing Steel, waserroneously written and printed as William B. Skikle, whereas said nameshouldhave been written and printed as William 2?; Skihkle, as shown bythe record of assignments in this oflice; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Ofiiee.

Signed and sealed this 7th day of November, A. D., 1922.

[BILL] KARL FENNING,

Acting Commissioner of PM.

